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I work for NuForce (oft-stated fact) and I’m
writing about a NuForce product (also
oft-stated). Readers will question my
impartiality, and so they should. I am
decidedly partial, having been much
impressed by NuForce amplification and its
piddling power demands before I signed on.
In a pre-employment review I expressed a
preference for NuForce monos to a pair of
yacht anchors that idled apiece at 200
watts. The relatively tiny NuForce pair was
smoother, better resolved and every bit as
perky.
So never
mind what I have to say (tho I’d love you to
read on). I fully expect disinterested
reviewers to find much to admire and little,
if anything, to criticize. Meanwhile, think
of this as a press release.
The P-20 delights the eye. Its angled face
is of a piece with the company’s high-end
gear. (NuForce identifies its lines as
Consumer and High-end.) The P-20 shares the
Reference 18 mono amp’s under-three-inch
height and seventeen-inch width – twice as
wide as my CDP-8 player-transport and DAC-9
converter’s similarly sculpted cases.
The single,
wide-chassis P-20 replaces the twin-box P-9.
I wasn’t a big fan of the predecessor’s
volume layout. With the P-9 set to operate
in a dimmed mode, the illuminated panel
would alternate between dim and bright when
the volume setting straddled levels – an
annoyance having no effect on the sound.
(Anyone on the prowl for a closeout deal
could do worse.) In keeping with the NuForce
standard, the P-9’s resolution, transparency
and lifelike presentation are exemplary.The
P-20 goes a step beyond. (It’s a matter of
ongoing fascination that what we perceive as
great sound proves infinitely elastic. Among
audiophiles, no difference for the better is
ever shrugged off as negligible.)
Consistent
with the CDP-8 transport, DAC-9 converter
and Ref 18 amp’s touch-sensitive panels, the
P-20’s panel replaces the P-9’s knobs.
Tasteful red-on-black displays accompany
turn-on and turn-off. (The DAC-9 retains a
small knob: a volume control for its
headphone amp.)
Listening
The sound of a factory-fresh unit: opaque.
No surprise. In a hi-rez system, immature
gear sits like a zit. Given the P-20’s
stated improvements, I knew enough to bide
my time.
I hear the
properly seasoned preamp’s merits as
heightened resolution, transparency and
dynamic finesse, which operate together as
soundstage enhancements. I have a better
sense of the music’s strands. Transients and
attacks are scalpel-sharp. A good recording
more closely imitates life than anything
I’ve experienced in this listening room. The
preamp is not forgiving, however.
Forgiveness, which is to say euphonious
coloration, is not a quality I’ve valued or
sought. The truth-telling Sasha W/Ps tell me
all I need to know about events upstream. A
great recording sings. Mediocrities croak.)
Recent and
related tweaks: I replaced the P-20’s fuse
with a Hi-Fi Tuning equivalent. These little
wonders also occupy my Ref 18 amps (fuses
earlier covered here). I’ve augmented the
speakers’ WP Supreme Quantum chips with the
same German maker’s cable chips. I’m
delighted with what I hear but have made no
recent A/B comparisons. (Another reason not
to take me too seriously. I’m lazy.)
***
The
Website’sP-20 statement and specs:
The P-20 Preamplifier’s elegantly sculpted
aluminum case encloses a number of
significant advances over the preamp’s
award-winning P-9 predecessor in several key
areas, especially with respect to volume
control. A preamp’s volume-control
capabilities are among its most critical
features. In practical terms, we saw room
for improvement over the already excellent
P-9’s volume control within the areas of
transparency and noise.
The P-20’s numerically controlled,
switched-resistor ladder network features
the last word in thin-film technology. In
order to improve precision and lower the
noise floor to the vanishing point, we’ve
implemented a single thin-film,
ultra-low-noise resistor in the signal path
for each of the volume control’s 0.5 dB gain
settings, thus permitting the listener to
achieve the desired volume level in precise
0.5 dB steps. As a further benefit, the
listener is able to adjust any input’s level
to exactly correspond with any other,
thereby simplifying the matching of
source-component volume levels.
The heart of the P-20 boasts an
all-discrete, fastidiously precise amplifier
module. Because speed is of paramount
significance, we’ve reduced capacitive
loading on the final voltage amp with the
implementation of ultra-low-noise,
monolithic dual JFETs, specially selected
VMOS FETs, and extremely flat hFE bipolar
transistors in a dual cascode configuration,
all of which are combined within a
driven-shield arrangement. The P-20 offers a
5 MHz power bandwidth, an S/N ratio
exceeding 100 dB, and a dynamic range in
excess of 120 dB. There are no capacitors or
DC-servos in the inherently stable P-20’s
gain circuit.
And, in keeping with these advances, we’ve
paid a great deal of attention to isolation.
We’ve covered the amplifier modules with
thermal insulation along with heavy copper
shields in order to avoid thermal drift or
signal-degrading heating effects. Each amp
module’s self-contained shunt regulator
further assists in isolation from power
supplies. A similarly isolated
floating-current source supply feeds each
module to insure separation from
ground-system noise.
Since all control functions are powered by
discrete power supplies, the P-20’s design
prevents any logic circuitry clock-signal
noise from ever contaminating the analog
section's low-level signals. In keeping with
the P-20’s state-of-the-art features, we
include a delightfully convenient,
custom-designed remote control. In sum, the
P-20’s near-to-molecular clarity offers the
last word in utterly transparent, organic
sound – in effect, a stress-free listening
experience as close to live as audio
permits. Better still, these features can be
activated by a 12V trigger signal enabling
system integration without the need for
manual intervention. All that’s required is
a processor or receiver with a common 12V
trigger connection.”
Specifications
• Inputs: 1 XLR, 5 RCA
• Outputs: 1 RCA, 1 XLR
• THD+N at 1kHz = 0.0006% at 20-20kHz =
0.003% at DC to 1MHz: < 0.05 %
• S/N = 100dB at 20-20kHz S/N > 90dB at DC
to 1MHz
• Frequency Response at 20-20kHz =
+0.02dB/-0dB at DC to 1Mhz = +0.5dB/-0dB at
DC-2.5 MHz +0/-3dB
• Maximum output: 7V RMS
• Phase shift = 0
• Input impedance = 10K ohm
• Output impedance = 100 ohm
• Dimensions : 17"W x 15"D x 1.97"H (2.56"H
include feet)
• Weight: 17 lbs
• Power 120V 60Hz (100V and 240V models
available)
Chassis available in black or silver
anodized aluminum.
The P-20 has a three-year warranty.
Features
• Ultra low noise 1nV/√ Hz JFETs
• Volume control features numerically
controlled, switched-resistor ladder network
with the latest in thin-film,
ultra-low-noise resistor technology
• Full microprocessor control with memory
retention
• No capacitor and no DC-servo in the signal
path
• 3 separate power supplies
• Individual audio channels are shielded
with heavy copper shield with thermal
barrier
• Solid stainless steel back connector panel
forms a solid signal ground reference
And there you have it.
***
NuForce
382 South Abbott Avenue
Milpitas, CA 95035
www.nuforce.com
salesteam@nuforce.com
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